Bows have been used for thousands of years as a tool for rapidly propelling an arrow. The simplest bow designs have included a body made of a single piece of material—usually wood. The body is shaped to include flexible limbs at each end. A bow string is securely fastened between the flexible limbs. When the bow string is pulled, the force causes the limbs to bend. When the string is released, the reduced force causes the limbs to spring back to their original position, thereby propelling an arrow.
In recent years major advances in bow technology have occurred. One major advance is the development of the compound bow. A compound bow typically includes pulleys and cams that provide added mechanical advantage. As a result, a compound bow may be both easier to draw and also more powerful than prior bow technology.